During the first few days of germination, the RNA content of the cotyledons remained approximately constant, but the quantity of membrane-bound ribosomes increased. Experiments with orthophosphate-32P indicated that these ribosomes were synthesisedde novo, and did not originate by the attachment to membranes of pre-existing free ribosomes. This conclusion was discussed in relation to the suggestion that free and membrane-bound ribosomes synthesise different groups of proteins.
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